BRITAIN could be forced to leave the EU if the debt crisis in Europe continues, a leading investment bank has warned.

Japanese investment bank, Nomura issued a stark prediction that it is 'increasingly likely' that Britain will exit the European Union.

In a report to clients, analysts said a perfect storm of coalition tensions, declining British influence in Europe and moves for closer EU integration risks an all-out referendum before 2015.

Penned by former British diplomat and Tony Blair adviser Alastair Newton, the report added that, without a repatriation of powers, it would be difficult to get Britons to vote to stay in Europe – forcing a British exit, from the EU.

He said: "In short, we see a non-negligible probability that, however the question put to the electorate was worded, a referendum on EU membership without first securing significant concessions from EU partners would result in the UK leaving the European Union.

We see difficulty securing an ‘in’ vote no matter how the question is framed

“We see difficulty securing an ‘in’ vote no matter how the question is framed.”

David Cameron has come under increasing pressure to call for a referendum on EU membership - a thing which the Daily Express has long campaigned for.

It is the first time a financial institution has predicted that Britain could leave the EU.

The comments follow those of former PM Tony Blair who said he was 'deeply worried ' that Britain could leave the EU if they lost any more powers to Brussels.

The former British Prime Minister told a German newspaper that he was concerned that Britain would call for a referendum on the EU and that the country would choose to opt out.

Blair told Die Zeit newspaper that it was clear the eurozone crisis had had a negative effect on people's perceptions of the EU in Britain and that the crisis would lead to a 'powerful political change' which would see Brussels claim more power over the nations belonging to it.

Tory MP Douglas Carswell said: “I think it’s wonderful to see that the City and the banks are beginning to recognise reality."